Magnetic jig for electroplating



w. B'ELLWOD 2,505,531

MAGNETIC JIG FOR ELECTROPLATING Filed Dec. 31. 1947 2 Shee'ts Sfiet 1INVENTOR W B. ELLWOO G N I an mm om Wm Hm M m m .J We I m N G A M 2Sheets-Sheet 2 Filed Dec. 31, 1947 SOURCE OF CURRE/V 7' D.C.$UPPLY FORFLA TING F OR FIG.

lNl/ENTOR B. ELL W000 ATTORNEY Patented Apr. 25, 195% STATES PATENTOFHQE MAGNETIC JIG FOR ELECTROPLATING Application December 31, 1947,Serial No. 795,029.

2 Claims.

This invention relates to electromagnetically operated switches andparticularly to sealed wire type or switch in which the magneticallymovable members also act at the contact device. Switches of this kindconsist generally of a tiny glass tube with themagnetiewires sealed inat the ends of the tube and immersed in an inert gas. These contactunits are then inserted into solenoids so that the air-gap of thecoinpletedrelay'comes substantially at the point in the center of thecoil where the greatest efiiciency is obtained.

The object of the invention is to provide a method whereby contact unitsof great uniformity may be produced economically. Due to the small sizeof the contact units the extremely small movement of the wires andthefact that no adjustments can be made after the reeds have been sealedinto the tubes, great accuracy, skill and care must be exercised inproducing such units. One of the factors in the uniformity of theproduct and the economy with which the wires are formed is theelectroplating process.

In accordance with this object a jig is provided by which a largeplurality of wires are magnetically. held imposition each in its ownelectrical circuit as a cathode in the electroplating process and bywhich they may all be simultaneously dropped into a washing bath at theend of the electroplating process without being handled by an operator.

By way of example, a jig for this purpose consists of a solenoid toenergize approximately one hundred separate magnetic cores orpole-pieces. These ole pieces are all of the same length so that theirsurfaces are in the same plane. The other end of each magneticpole-piece is connected through an individual IOO-ohm resistance to acommon cathode circuit. Spaced below these pole-pieces is a piece ofinsulation with one hundred holes drilled therethrough to guide thewires to be electroplated to the pole-pieces. When the magnet isenergized, one hundred of the wires may be placed through these holesand will be firmly held against the pole-pieces so that the jig as anentirety may be turned about and the wires suspendedas separate cathodesin an electroplating bath.

The magnet may be energized by direct current in which cas the wireswill be held immobile. As an alternative having certain advantages thecoil may be energized by alternating current in which case there is somevibration of the wires so that when suspended in th electrolyte, gasbubbles will be shaken away from the immersed ends.

When the electroplating process is completed,

2 the jig as a whole is moved away from the electroplating bath, heldover a washing bath and the current through the magnetizing coil isbroken whereupon the one hundred wires will fall by gravitysimultaneously into the washing bath.

As a specific embodiment of the inventionthe wires formed of an alloy ofiron and "nickel are electroplated with rhodium. The use of rhodium as acontact metal has certain advantages. The peculiar properties of thismetal which render it valuabl for this use are its extreme hardness andits high melting point combined with its low specific resistance andhigh covering power'as a plating material. The hardness is of valuebecause it acts as a retaining sheath for the very malleable nickel andiron alloy'and thereby prevents more than a slight deformation of thetips of the wires under the magnetic impact ofsuch wires on operation ofthe device'f Its high melting point prevents destruction of the contacttips under the rapid magnetichammering 'in' the torrnation of thecontact surfaces'and its low specific resistance makes it especiallyuseful as acontact metal. Thehigh covering power makes an extremely thincoat without pinholes and gives excellent protection against oxidationof the base material.

' The drawings consist of two sheets having four figures as follows:

Fig. 1 is an enlarged perspective view partly broken away of the jig forholding the wires during the electroplating process;

' Fig. 2 is a side view of the jig in its relation to the other parts ofthe apparatus during the electroplating process;

' Fig. 3 is a cross-sectional view taken on the line 33 of Fig 2; and

Fig. 4 is a view partly in outline of the contact device which employsthese electroplated wires.

The jig is made on a framework of two metallic channel pieces I and 2.To these are secured two side pieces 3 and 4;. A cross-piece 5 issecured to the channels 1 and 2 and forms a basis for inserting aplurality of iron pieces such as the fiatheaded screws 6, 1, etc. Attheir threaded ends these screws thread into a piece of insulatingmaterial 8 so that the screws are held securely in place. At their headends each screw has soldered to it a separate -ohm resistor, such asthere'- sistor 9,all of which are connected in multiple and leadtoa'socket l0. cross-piece H is provided by means of which the variouselements of the jig maybe securely attached and held togetherby thescrews Hand [3. Between the insulating piecest and 8, insulatingbushings l4 and I 5 are placed and at the bottom of the device anotherpiece of insulating material it is secured in the assembly and held bythe nuts H and 18. This piece is drilled with a number of holescorresponding to the number of the iron pieces 6 and i so that the wiresI9, 29, etc. inserted in these drilled holes will each come to rest onthe end of an iron piece. The drilled holes are only slightly largerthan the wires to be inserted therethrough so that such wires may beheld in position without binding. When the device has been assembled,the lowe ends of the iron pieces are ground to an even level and arepreferably goldplated to prevent rusting during the life and use of theapparatus.

A coil 2! is wound about the iron pieces so that when energized,preferably by direct current, each one of the iron rods will bemagnetized so as to hold the alloy wires in position magnetically. Theterminals of the coil 2! are brought out to a socket 27. so as toprovide a flexible connection between the source of current and the jig.Usually the jig is placed in such a position that the wires may bedropped from above through the holes in the piece I6. After thisoperation has been completed the source of current is connected to thecoil 2| and the jig placed in the position for the electroplatingprocess.

Fig. 2 shows the position in which the jig is placed during theelectroplating process. A pair of spring supports 23 and 24 is providedwhich is engaged by centering pins 25 and 26. A container 21 suitablysupported contains the electroplating solution 28 and an anode 29. Theanode 29 and the multiple connection through the socket iii to theplurality of resistance coils and thence to the wires to beelectroplated are connected to a suitable source of direct current sothat as these wires dip into the solution they will becomeelectroplated. In order to provide a certain amount of agitation, anelectric motor 30 will operate an eccentric cam 3| to give the jig aback and forth motion. In order to adjust the level of the solution 28so that the wires will all be plated for a uniform distance, a pair ofshortened wires 32 and 33 is placed in the end positions and then thecontainer 21 is raised or lowered by any suitable means until thesurface of the solution just reaches these shortened wires.

In the electroplating process the jig with its wires held magneticallyin place is generally first placed over another tray of acid and thewires connected as anodes so as to thoroughly clean the surfaces thatare to be electroplated. When this process has been carried on for avery few minutes the jig is lifted from the acid solution and placedmomentarily in a tray of distilled water and then placed in theelectroplating solution as shown in Figs. 2 and 3. When theelectroplating process has been completed the jig is lifted bodily fromits supports 23 and 24 and held over a tray of distilled water. Thesource of current to the magnetizing coil 2| is then broken so that thewires now electroplated may be dropped into this tray of distilled waterto be cleaned free from electrolyte.

The wires thus electroplated may be used as the elements of aglass-sealed contact device shown in outline in Fig. 4. Here, two of thewires 36 and 35 are shown sealed into either end of a glass tube 36which is filled with a noncorrosive gas such as helium. The overlappingends of these two wires are electroplated and held normally at a shortdistance from each other. When such a unit is placed within a helix itforms an efficient and very fast acting contact device for which thehelix is energized by the flow of current therethrough the magneticeffect will bring the two overlapping ends of the wires together so thatan electrical circuit may be completed therethrough.

These wires as shown are parallel to each other and hence the contactmade between them when they are drawn together is at least theoreticallyalong a geometrically straight line or even at a geometrical point. Inorder to render this device an efficient contactor, contact surfaces areformed by placing the device in a magnetic circuit and hammering theseoverlapping ends together rapidly by connecting the helix to a source ofalternating current. Since the wires are of a malleable nature this soonforms two conforming surfaces on the wires. The use of rhodium as aplating material is of special value since it is extremely hard and itshigh melting point renders it valuable as a sheath so as to prevent morethan a slight deformation of the tips of the wires in this operation.Its high melting point prevents destruction of the contact tips underthe rapid magnetic hammering in the formation of these contact surfacesand its low specific resistance makes it especially useful as a contactmaterial.

What is claimed is:

l. A jig for positioning magnetic material wires in an electroplatingbath consisting of a solenoid encompassing a plurality of magnetic corescoordinately arranged, each. having an end face in the same plane andeach being electrically insulated from the others. a guide for guidingeach separate wire to be electro lated consisting of a slab ofinsulating material mounted in a plane parallel to the said'plane ofsaid core end faces and having a hole only slightly larger than andconforming in shape to the wire to be guided thereby for each of saidmagnetic cores constructed along the axis of each said core, a separateresistance element connected to the other end of each said core, saidresistance elements having their other terminals multiplied to a commonwire whereby a plurality of wires to be electroplated may bemagnetically suspended through energization of said solenoid whi e eachis connected in an individual electrical circuit by electricalconnection to the face of the said core to which it is attracted andrestrained from lateral movement away from its own axis and the axis ofsaid core from which it is suspended.

2. A jig for positioning magnetic material wires in an electroplatingbath consisting of a solenoid encompassing a plurality of magnetic corescoordinately arranged, each having an end face in the same plane andeach being electrically insulated from the others, a guide for guidingeach separate wire to be electroplated consisting of a slab ofinsulating material mounted in a plane parallel to the said plane ofsaid core end faces and having a hole only slightly larger than andconforming in shape to the wire to be guided thereby for each of saidmagnetic cores constructed along the axis of each said core, a

separate resistance element connected to the other end of each saidcore, said resistance elements having their other terminals multipled toa common wire whereby a plurality of wires to be electroplated may bemagnetically suspended through energization of said solenoid while eachis connected in an individual electrical circuit by electricalconnection to the face 3 of the said core to which it is attracted andre strained from lateral movement away from its own axis and thej axisof the said core-from which it is suspended, and means to control theenergization and deenergization of said solenoid 5 REFERENCES CITED Thefollowing references are of record in the file 01 this patent:

6 UNITED STATES PA'I'ENTS Number Name Date 1,168,280 Buch Jan. 18, 19162,438,897 Brown Apr. 6, 1948 FOREIGN PATENTS Number Country Date 353,332Great Britain July 23, 1931

